Order Code RL33413
Automobile and Light Truck Fuel Economy:
The CAFE Standards
Updated June 1, 2007
Brent D. Yacobucci
Specialist in Energy Policy
Resources, Science, and Industry Division
Robert Bamberger
Specialist in Energy Policy
Resources, Science, and Industry Division

Automobile and Light Truck Fuel Economy:
The CAFE Standards
Summary
High crude oil and gasoline prices have renewed the focus on U.S. fuel
consumption in the transportation sector and federal Corporate Average Fuel
Economy (CAFE) standards. Wider concerns over greenhouse gas emissions and
climate change have contributed to interest in reducing fossil fuel consumption and
improving the efficiency of the U.S. transportation sector.
CAFE standards are fleetwide fuel economy averages that manufacturers must
meet each model year. Currently, separate CAFE standards are established for
passenger cars and light trucks (which include SUVs, vans, and pickups). Several
bills affecting the program have been introduced in the 110th Congress. They differ
in their provisions, but may include language to increase the CAFE standards for all
vehicles, change fuel economy testing procedures to make more conservative
measurements of consumer-experienced on-road fuel economy, establish a system
to trade CAFE credits among manufacturers, and grant the National Highway Traffic
Safety Administration (NHTSA) broader authority to implement the program.
On May 8, 2007, the Senate Committee on Commerce, Science &
Transportation ordered S. 357 (Feinstein) reported with amendments. The amended
bill would increase fuel economy standards for both passenger cars and light trucks,
among other provisions. The bill has been included in S. 1419, the Renewable Fuels,
Consumer Protection, and Energy Efficiency Act of 2007.
On February 6, 2007, NHTSA submitted draft legislation to the House Energy
and Commerce Committee. In the submission, NHTSA requested that Congress
grant the agency authority to increase passenger car CAFE standards and to establish
an attribute-based system for passenger cars. The Energy Policy and Conservation
Act (EPCA) of 1975 grants NHTSA the authority to alter the light truck program’s
structure, but the passenger car program is set by EPCA. Under EPCA, NHTSA
lacks the authority to alter the structure or the fuel economy targets of the passenger
car program. As part of the Administration proposal, NHTSA also requested the
authority to allow credit trading among different manufacturers; currently,
manufacturers may bank credits for future years but may not trade them to other
manufacturers.
On April 6, 2006, NHTSA released a final rulemaking for sport utility vehicles
(SUVs) and light-duty trucks beginning with model year (MY) 2008. The rule
restructures the CAFE program for light trucks to establish standards based upon
vehicle size, as opposed to the current program with one average standard for all light
trucks. It marks a significant change to the CAFE program for trucks. The sharp rise
in gasoline prices during spring 2006 focused attention on the CAFE standards for
passenger cars, and on the fact that NHTSA does not have the same latitude to make
changes to passenger car CAFE or the passenger car CAFE program.
This CRS report replaces CRS Issue Brief IB90122, Automobile and Light
Truck Fuel Economy: The CAFE Standards.

Contents
Most Recent Developments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
Origins of CAFE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
Past Role of CAFE Standards . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
Authority To Amend CAFE Standards . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
NHTSA Rulemaking for MY2008-MY2011: Light Truck Fuel Economy . . . . . . 6
Unreformed Standards . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Reformed Standards . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Medium-Duty Passenger Vehicles . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
CAFE in the 110th Congress . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
CAFE in the 109th Congress: Omnibus Energy Legislation (P.L. 109-58) . . . . . 10
Feasibility Report . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
In-Use Fuel Economy Estimates . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
Improving Fuel Economy: Other Policy Approaches . . . . . . . . . . . . . . . . . . . . . 11
The Hydrogen Fuel Initiative and FreedomCAR . . . . . . . . . . . . . . . . . . . . . 11
Price of Gasoline . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
CAFE and Reduction of Carbon Dioxide Emissions . . . . . . . . . . . . . . . . . . 12
For Additional Reading . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
List of Figures
Figure 1. Passenger Car and Light Truck Fuel Economy Averages
for Model Years 1978-2005 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
Figure 2. Light Truck CAFE Standards for Various Model Years . . . . . . . . . . . . 8
List of Tables
Table 1. Fuel Economy Standards for Passenger Cars
and Light Trucks: Model Years 2000 Through 2011 . . . . . . . . . . . . . . . . . . . 2
Table 2. Estimated Costs and Benefits
from the MY2008-MY2011 Reformed Light Truck CAFE Standards . . . . . 8

Automobile and Light Truck Fuel Economy:
The CAFE Standards
Most Recent Developments
On May 8, 2007, the Senate Committee on Commerce, Science &
Transportation ordered S. 357 (Feinstein) reported with amendments. The amended
bill would increase fuel economy standards to 35 miles per gallon by 2020 for
passenger cars and light trucks combined. Other provisions include the requirement
that a percentage of automakers’ new vehicles be alternative fuel-capable starting in
2012, and that CAFE fines be used to develop alternative fuel infrastructure. The bill
has been included in S. 1419, the Renewable Fuels, Consumer Protection, and
Energy Efficiency Act of 2007.
On February 6, 2007, the National Highway Traffic Safety Administration
(NHTSA) submitted draft legislation to the House Energy and Commerce Committee
to modify the Corporate Average Fuel Economy (CAFE) program for passenger cars.

CRS-2
The Energy Policy and Conservation Act (EPCA) of 19751 grants NHTSA the
authority to alter the light truck CAFE program’s structure, but several features of the
passenger car program cannot be altered by NHTSA under EPCA. For example, to
increase passenger car CAFE above the current 27.5 miles per gallon (mpg), the
President must submit the proposal to Congress, which can then act to disapprove;
otherwise, the proposal goes into effect. Further, NHTSA lacks the authority to alter
the structure of the passenger car program. In its submission, NHTSA requested that
Congress grant the agency authority to increase passenger car CAFE standards and
to establish an attribute-based system for passenger cars. As part of the
Administration proposal, NHTSA also requested the authority to allow credit trading
among different manufacturers; currently, manufacturers may bank credits for future
years but may not trade them to other manufacturers.
On April 6, 2006, NHTSA released a final rulemaking for sport utility vehicles
(SUVs) and light-duty trucks beginning with model year (MY) 2008. The rule
restructured the corporate CAFE program for light trucks to establish standards based
upon vehicle size, as opposed to the current program that has one average standard
for all light trucks. It marked a significant change to the CAFE program for trucks.
The final rule also drew attention to the fact that NHTSA does not have the same
latitude to make changes to passenger car CAFE or the passenger car CAFE program.
1 P.L. 94-163.

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Origins of CAFE
The Arab oil embargo of 1973-1974 and the subsequent tripling in the price of
crude oil brought into sharp focus the fuel inefficiency of U.S. automobiles. New car
fleet fuel economy had declined from 14.8 miles per gallon (mpg) in model year
(MY) 1967 to 12.9 mpg in 1974. In the search for ways to reduce dependence on
imported oil, automobiles were an obvious target. The Energy Policy and
Conservation Act (EPCA) established CAFE standards for passenger cars for MY
1978. The CAFE standards called for an eventual doubling in new car fleet fuel
economy. EPCA also granted NHTSA the authority to establish CAFE standards for
other classes of vehicles, including light-duty trucks.2 NHTSA established fuel
economy standards for light trucks, beginning in MY1979. For passenger cars, the
current standard is 27.5 mpg. For light trucks, the standard is 22.2 mpg for MY2007.
On April 6, 2006, NHTSA issued additional rules to further increase light truck fuel
economy through MY2011. (The CAFE standards to MY2011 are summarized in
Table 1.)
Table 1. Fuel Economy Standards for Passenger Cars and
Light Trucks: Model Years 2000 Through 2011
(miles per gallon)
Passenger
Light
Model year
cars
trucksa
2000
b27.5
20.7
2001
b27.5
20.7
2002
b27.5
20.7
2003
b27.5
20.7
2004
b27.5
20.7
2005
b27.5
21.0
2006
b27.5
21.6
2007
b27.5
22.2
2008
b27.5
c22.5
2009
b27.5
c23.1
2010
b27.5
c23.5
2011
b27.5
d24.0
Source: Automotive Fuel Economy Program, Annual Update, Calendar Year 2001; U.S. Department
of Transportation. National Highway Traffic Safety Administration, Light Truck Average Fuel
Economy Standard, Model Year 2004
, Final Rule; and U.S. Department of Transportation, National
Highway Traffic Safety Administration. Average Fuel Economy Standards for Light Trucks Model
Years 2008-2011
, Final Rule.
a. Standards for MY1979 light trucks were established for vehicles with a gross vehicle weight rating
(GVWR) of 6,000 pounds or less. Standards for MY1980 to MY2000 are for light trucks with
a GVWR of 8,500 pounds or less. Starting in MY2011, the light truck CAFE program will
include medium duty passenger vehicle (MDPVs), trucks with a GVWR between 8,500 and
10,000 pounds that primarily transport passengers (e.g., large SUVs, passenger vans)
b. Established by Congress in Title V of the act.
c. Unreformed CAFE standard.
d. Estimated average based on MY2011 reformed standard.
2 Light-duty trucks include most sport utility vehicles (SUVs), vans, and pickup trucks.

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Under EPCA, the Secretary of Transportation has the discretion to adjust the
passenger car standard within a range of 26.0 to 27.5 mpg. If NHTSA amends the
standard above 27.5 mpg or below 26.0 mpg, that amendment must be submitted to
Congress. If either House of Congress disapproves of the amendment within 60
days, it does not take effect. However, the use of this “one-house veto” would likely
be judged unconstitutional, so the likelihood of Congress stopping an amendment to
CAFE in this manner is questionable.3 The Secretary has much broader discretion
with respect to setting light truck (referred to in the regulations as “non-passenger
automobiles”) fuel economy standards, including the authority to establish different
standards for different classifications of these vehicles.
Compliance with the standards is measured by calculating a sales-weighted
mean of the fuel economies of a given manufacturer’s product line, with domestically
produced and imported cars measured separately. The penalty for non-compliance
is $5.50 for every 0.1 mpg below the standard, multiplied by the number of cars in
the manufacturer’s new car fleet for that year. Civil penalties collected from 1983
to 2003 totaled slightly more than $600 million. However, these penalties have been
paid mostly by small and speciality European manufacturers, not by the major U.S.
or Japanese automotive manufacturers.
When oil prices rose sharply in the early 1980s, smaller cars were selling well,
and it was expected that manufacturers would have no difficulty complying with the
standards. However, oil prices had declined by 1985. Sales of smaller cars tapered
off as consumers began to place less value on fuel economy and gasoline cost as an
input in the overall costs of vehicle ownership. In response to petitions from
manufacturers facing stiff civil penalties for noncompliance, NHTSA relaxed the
standard for model years 1986-1989, but it was restored to 27.5 in MY1990. The
Persian Gulf War in 1990 caused a brief spike in oil prices, but it also demonstrated
that it was unlikely that the United States or many of the producing nations would
tolerate a prolonged disruption in international petroleum commerce. As a
consequence, U.S. dependence upon imported petroleum, from a policy perspective,
was considered less of a vulnerability.
It was also becoming apparent that reducing U.S. dependence on imported oil
would be extremely difficult without imposing a large price increase on gasoline, or
restricting consumer choice in passenger vehicles. Many argued (and still do) that
the impacts of such actions upon the economy or the automotive industry would be
unacceptable. Meanwhile, gasoline consumption, averaged 6.5 million barrels per
day (mbd) in 1982, increased to nearly 8.4 mbd in 1999, and was roughly 9.3 mbd
in the winter of 2007 after peaking at 9.6 mbd during the summer of 2006.
Past Role of CAFE Standards
The effectiveness of the CAFE standards themselves has been controversial.
Since 1974, domestic new car fuel economy has roughly doubled; the fuel economy
of imports has increased by roughly one-third. Some argue that these improvements
3 For more discussion on the constitutionality of one-house vetoes, see CRS Report
RS22132, Legislative Vetoes After Chada, by Louis Fisher.

CRS-5
would have happened as a consequence of rising oil prices during the 1970s and
1980s regardless of the existence of the CAFE standards. Some studies suggest that
the majority of the gains in passenger car fuel economy during the 1970s and 1980s
were technical achievements, rather than the consequence of consumers’ favoring
smaller cars. Between 1976 and 1989, roughly 70% of the improvement in fuel
economy was the result of weight reduction, improvements in transmissions and
aerodynamics, wider use of front-wheel drive, and use of fuel-injection. The fact that
overall passenger car fleet fuel economy remained comparatively flat during a period
of declining real prices for gasoline also suggested that the CAFE regulations have
contributed to placing some sort of floor under new-car fuel economy. Recent and
historic fleet fuel economy averages are shown in Figure 1.
Figure 1. Passenger Car and Light Truck Fuel Economy
Averages for Model Years 1978-2005
30
28
26
24
22
20
18
16
1978
1983
1988
1993
1998
2003
Automobiles
Light Trucks
Combined
Source: U.S. Department of Transportation, National Highway Traffic Safety Administration,
Summary of Fuel Economy Performance, March 2005.
General criticisms of raising the CAFE standards have been that, owing to the
significant lead times manufacturers need to change model lines and because of the
time needed for the vehicle fleet to turn over, increasing CAFE is a slow and
inefficient means of achieving reductions in fuel consumption. Further, it is argued
that the standards risk interfering with consumer choice and jeopardize the economic
well-being of the automotive industry. Opponents of raising CAFE usually cite fears
that higher efficiency will likely be obtained by downsizing vehicle size and weight,
raising concerns about safety.
Proponents of CAFE increases have argued that boosting the standards might
bring about the introduction of technological improvements that do not compromise
features that consumers value, but which would otherwise not be added because these
improvements do add to the cost of a new vehicle.

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There were highly controversial attempts to significantly raise the CAFE
standards on passenger cars in the early 1990s. One proposal included in omnibus
energy legislation was so controversial that it contributed to the Senate’s inability in
1991 to bring the bill up for debate on the floor.
NHTSA typically established truck CAFE standards 18 months prior to the
beginning of each model year, as EPCA allows. However, such a narrow window
permitted NHTSA to do little more than ratify manufacturers’ projections for the
model year in question. In April 1994, the agency proposed to abandon this practice
and issued an Advance Notice of Proposed Rulemaking inviting comment on what
level that standards might be established for trucks for MY1998-MY2006. The
following year, however, after a change in congressional leadership, Congress
included language in the FY1996 Department of Transportation (DOT) Appropria-
tions to prohibit expenditures for any rulemaking that would make any adjustment
to the CAFE standards. Identical language was included in the appropriations and
spending bills for FY1997-FY2000. An effort to pass a sense of the Senate
amendment that conferees on the FY2000 DOT Appropriations should not agree to
the House-passed CAFE rider for FY2000 was defeated in the Senate on September
15, 1999 (55-40). The rider also appeared in the FY2001 DOT Appropriations (H.R.
4475) approved by the House Committee on Appropriations May 16, 2000, and
approved by the House May 19, 2000. However, the Senate insisted that the
language be dropped in conference, opening the way for NHTSA to initiate
rulemakings once again.
The conferees also agreed to authorize a study of CAFE by the National
Academy of Sciences (NAS) in conjunction with DOT. That study, Effectiveness and
Impact of Corporate Average Fuel Economy (CAFE) Standards
, released on July 30,
2001, concluded that it was possible to achieve more than a 40% improvement in
light truck and SUV fuel economy over a 10-15 year period at costs that would be
recoverable over the lifetime of vehicle ownership. A study released in December
2004 by the National Commission on Energy Policy, Ending the Energy Stalemate:
A Bipartisan Strategy to Meet America’s Energy Challenges
, established by
foundation money, recommended that Congress instruct NHTSA to raise CAFE
standards over a five-year period beginning not later than 2010. The commission
recommended that manufacturers be able to trade fuel economy credits earned by
exceeding the standards.
Authority To Amend CAFE Standards
A major issue that has arisen out of the sharp increase in gasoline prices since
the spring of 2006 is whether NHTSA has authority to change fuel economy
standards. Title 49, Chapter 329, of the U.S. Code grants NHTSA broad authority
to establish both the structure and the targets for light truck fuel economy. This is the
authority NHTSA used to establish fuel economy standards for MY2005-MY2007
and to modify the structure of the light truck fuel economy program — as well as the
standards — for MY2008-MY2011.

CRS-7
In contrast, NHTSA’s authority to modify passenger car standards is limited,
and NHTSA has no authority to alter the structure of the passenger car program. As
required by 49 U.S.C. 32902, the average fuel economy of a manufacturer’s
passenger car fleet must equal or exceed 27.5 mpg (the passenger car CAFE
standard). Moreover, NHTSA has the authority to establish a different CAFE
standard, as long as that standard falls between 26.0 and 27.5 mpg. Any change
above 27.5 mpg or below 26.0 mpg requires the Secretary of Transportation to issue
an amendment; that amendment is to be in force unless either House of Congress
disapproves. (However, as noted above, this one-House veto could be judged to be
unconstitutional.)
NHTSA has no authority to modify the structure of the passenger car program.
While 49 U.S.C. 32904 grants NHTSA the authority to develop procedures for
calculating a manufacturer’s average light truck fuel economy by regulation, this
section specifically establishes the procedures for calculating a manufacturer’s
passenger car fuel economy. Consequently, while NHTSA has the authority to
develop attribute-based standards for light trucks, the agency must use the straight-
line average for passenger cars.
On February 6, 2007, NHTSA asked Congress for the statutory authority to
develop passenger car standards similar to those established for light trucks. (A
similar request sent to the 109th Congress received no action.)
NHTSA Rulemaking for MY2008-MY2011:
Light Truck Fuel Economy
Today, light trucks — which include most SUVs and vans — are a larger
portion of the total vehicle population, and travel more annual vehicle miles, than in
the past. For example, in 1980, light trucks composed 20% of the U.S. new
automobile market. By 2006, this figure had increased to 55%; SUVs alone
accounted for 27% of the new vehicle market in 2005, while mini-vans accounted for
6.6%. However, a comparison of market share underestimates this growth and its
consequences. While the number of passenger cars sold each year in the United
States has decreased somewhat since 1980, the number of light trucks sold has nearly
quadrupled, from 2.2 million in 1980 to 9.2 million in 2005. As a result, the total
fuel usage attributable to these vehicles has increased.
On April 6, 2006, NHTSA issued a Final Rule increasing the stringency of the
light truck fuel economy program, as well as restructuring the program to incorporate
size-based standards. Under the new “reformed” system, each light truck will have
a fuel economy “target” based on its footprint (the product of wheelbase and track
width), with higher targets for smaller vehicles and lower targets for larger vehicles.
Under the reformed system, in a given model year the targets for a manufacturer’s
fleet are averaged to calculate that manufacturer’s mandated fuel economy. To
provide flexibility for manufacturers, between MY2008 and MY2010, manufacturers
may opt for either the reformed or unreformed systems. Starting in MY2011, all
manufacturers will be subject to the reformed system. Further, starting in MY2011,
medium-duty passenger vehicles (MDPVs) — vehicles between 8,500 pounds and

CRS-8
10,000 pounds gross vehicle weight that primarily transport passengers — will be
subject to CAFE standards for the first time. This class of vehicles includes large
SUVs and passenger vans, but does not include vehicles such as pickup trucks or
panel trucks. NHTSA estimates that the reformed system will lead to a light truck
average fuel economy of 24.0 mpg in MY2011, compared with a 22.2 mpg standard
in MY2007 and an estimated fuel economy of 21.8 mpg in MY2005. NHTSA
estimates that these changes will save 4.4 billion gallons over the life of the vehicles
produced between MY2008 and MY2011.
Unreformed Standards
Between MY2008 and MY2010, manufacturers may opt for either the reformed
or unreformed standards. The unreformed standards employ the existing system of
a single mandated average for all light trucks in a manufacturer’s fleet. From the
MY2007 standard of 22.2 mpg, the unreformed standards will increase to 22.5 mpg
in 2008, 23.1 mpg in 2009, and 23.5 in 2010.
During this period, NHTSA estimates that under the unreformed standards, the
average incremental cost increase will be $64 in MY2008 and $195 in MY2010.
Reformed Standards
One of the key criticisms of the existing CAFE structure is that increased CAFE
standards promote smaller, lighter vehicles. Because fuel economy tends to decrease
as vehicles get heavier, a simple way to increase fuel economy is to decrease vehicle
weight. However, larger vehicles tend to offer greater passenger protection in
accidents, and larger vehicles tend to be heavier. Therefore, a fuel economy standard
that does not take vehicle size into account may promote the use of smaller, less safe
vehicles. A further criticism of the existing structure is that it favors producers of
smaller vehicles — vehicles that tend to have higher fuel economy. However, some
proponents of higher CAFE argue that through the use of new technology, vehicle
efficiency can be improved without affecting size or performance.
To address concerns over vehicle safety, NHTSA developed a new CAFE
structure that bases fuel economy on vehicle size, with smaller vehicles required to
achieve higher fuel economy than larger vehicles. Under the new system, each
vehicle is assigned a fuel economy “target” based on its footprint, which is the
product of a vehicle’s track width (the horizontal distance between the tires) and its
wheelbase (the distance from the front to the rear axles). The average of the targets
for a manufacturer’s fleet is the CAFE average that manufacturer must achieve in a
given model year. In this way, no specific vehicle is required to meet a specific fuel
economy; but the average fuel economy required will vary from manufacturer to
manufacturer. Manufacturers that produce smaller trucks will face higher CAFE
requirements for those vehicles; those that produce larger trucks will face lower
CAFE requirements for the larger vehicles. Figure 2 shows the targets for MY2011,
as compared to the unreformed MY2010 standard, and the MY2007 standard for all
light trucks.

CRS-9
Figure 2. Light Truck CAFE Standards for
Various Model Years
35
30
llon
a
r G
25
pe
s
ile
M
20
15
20
30
40
50
60
70
80
Footprint (square feet)
Reformed - MY2011
Unreformed - MY2010
Unreformed - MY2007
Source: CRS Analysis of 71 Federal Register 17566-17679, April 6, 2006.
NHTSA estimates that the reformed standards will add $66 to the cost of a new
vehicle in MY2008 and $271 in MY2011. NHTSA estimates total incremental costs
at approximately $550 million for MY2008, and $2,500 million for MY2011.
Further, the agency estimates the total benefits from reduced fuel consumption to be
roughly $780 million and $3,000 million in MY2008 and MY2011, respectively.
NHTSA’s estimates are shown in Table 2. It should be noted, however, that the
benefits from the rule were based on gasoline prices between $1.96 and $2.39 per
gallon. Higher fuel prices would increase the benefits from fuel savings, while lower
fuel prices would decrease the benefit.
Table 2. Estimated Costs and Benefits from the MY2008-
MY2011 Reformed Light Truck CAFE Standards
($ millions)
MY2008
MY2009
MY2010
MY2011
Total Incremental Cost
$553
$1,724
$1,903
$2,531
Total Incremental Benefit
$782
$2,015
$2,336
$2,992
Source: 71 Federal Register 17566-17679, April 6, 2006.

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Medium-Duty Passenger Vehicles
Starting in MY2011, medium-duty passenger vehicles (MDPVs) will be subject
to the same fuel economy standards as light trucks. MDPVs are vehicles between
8,500 and 10,000 pounds gross vehicle weight that are designed primarily to
transport passengers. Covered vehicles include most SUVs and passenger vans not
covered by the “light truck” definition; pickup trucks and panel trucks are excluded
from the requirements. Previously, MDPVs were not subject to CAFE standards.
Before MY2004, these vehicles were considered heavy-duty vehicles for both fuel
economy and emissions purposes. For the purposes of emissions standards, starting
in MY2004, the Environmental Protection Agency (EPA) first defined MDPVs and
included them in the “Tier 2" emissions standards for passenger cars and light trucks.
The justification at the time was that these vehicles are used primarily as passenger
vehicles, and should be regulated as such. NHTSA reached a similar conclusion,
adding that fuel economy standards for MDPVs were feasible, and that standards
would save additional fuel — approximately 250 million gallons over the operating
life of MY2011 MDPVs.
CAFE in the 110th Congress
Several bills have been introduced in the 110th Congress that would modify the
CAFE program to increase fuel economy standards for passenger cars and/or light
trucks, heighten the stringency of testing procedures, and/or grant NHTSA broader
authority to implement the program. One of these bills, S. 357, was ordered reported
favorably with an amendment in the nature of a substitute by the Senate Commerce
Committee on May 8, 2007. For background and analysis of the various CAFE bills,
see CRS Report RL33982, Corporate Average Fuel Economy (CAFE): A
Comparison of Selected Legislation in the 110th Congress
, by Brent D. Yacobucci
and Robert Bamberger.
Titled the “Ten-In-Ten Fuel Economy Act,” S. 357 proposes to create a single
vehicle class up to 10,000 pounds gross vehicle weight (gvw) beginning with model
year 2011, eliminating at that point the distinction between passenger automobiles
and light trucks. It would require the Secretary of Transportation to set “maximum
feasible fuel economy standards” during the period from MY2011-MY2020 with the
intention of achieving an overall fleet fuel economy average of 35 mpg. However, at
the discretion of the Secretary of Transportation, instead of establishing a single,
annual CAFE standard across a large population of vehicles of varying sizes and
purposes, a fuel economy target could be calculated for individual vehicles as a
mathematical function of an individual vehicle’s wheelbase — or footprint. Under
that scenario — and visualized on a graph — each year’s standard would no longer
be represented by a single line, but appear instead as a curve that would peg a
desirable fuel economy target for vehicles based upon their wheelbase. In successive
model years, the curve would be replotted, with the intention of reaching the 35 mpg
goal in MY2020.
For MY2021 through MY2030, the bill would require a 4% annual increase in
the CAFE target from the previous model year.

CRS-11
In setting fuel economy standards at “maximum feasible” levels, the Secretary
of Transportation will be required to consider factors including “economic
practicability” and the need of the nation to conserve energy. Standards must be
“technologically achievable,” may not compromise vehicle safety, and must be “cost-
effective.” The Secretary and NHTSA would be required to assess cost-effectiveness
against several criteria, including economic security, national security, foreign policy,
and the impact of oil use on various other national policy concerns. The bill has been
included in S. 1419, the Renewable Fuels, Consumer Protection, and Energy
Efficiency Act of 2007.

CAFE in the 109th Congress:
Omnibus Energy Legislation (P.L. 109-58)
The Energy Policy Act of 2005 (P.L. 109-58) authorized $3.5 million annually
during FY2006-FY2010 for NHTSA to carry out fuel economy rulemakings. It also
required a study (submitted to Congress in August 2006) to explore the feasibility
and effects of a significant reduction in fuel consumption by 2014, and required that
the estimated in-use fuel economy posted to the window of new vehicles more
closely approximate owners’ experience.
Feasibility Report
In response to the requirements of the Energy Policy Act of 2005, in August
2006, NHTSA issued to Congress the report “Study of Feasibility and Effects of
Reducing Use of Fuel for Automobiles.” The report concluded that NHTSA’s light
truck rulemaking will lead to significant reductions in fuel consumption, and that
granting NHTSA the authority to establish similar rules for passenger cars would lead
to even greater reductions.
In-Use Fuel Economy Estimates
The fuel economy of individual vehicles is calculated by running vehicles
through a test on a dynamometer intended to simulate a driving cycle that assumes
11 miles driven in an urban setting and 10 miles on open highway. To bring this
calculation more into line with in-use fuel economy experienced by drivers, the EPA
makes a downward adjustment of 10% for the city portion of the cycle and 22% for
the highway portion. However, many argued in the past that this adjustment was no
longer sufficient, and that the gap between estimated fuel economy and actual in-use
fuel economy had widened significantly.
EPACT requires a revision of the adjustment factor applied against tested
vehicle fuel economy to estimate consumer in-use fuel economy. On December 11,
2006, EPA finalized a rule to incorporate the effect of factors such as higher speed
limits, faster acceleration, differences in the ratio between city and highway driving,
and use of air conditioning on in-use fuel economy. The in-use fuel economy
stickers posted to the windows of new cars will reflect the results of these tests

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beginning in MY2008.4 This change will affect only the estimation of in-use fuel
economy. It will not affect the CAFE calculation for purposes of determining
manufacturers’ compliance with the CAFE standard.
Improving Fuel Economy: Other Policy Approaches
Two possible approaches to reduce gasoline consumption involve (1) raising the
price of gasoline through taxation, or other means, to a level that induces some
conservation; and (2) increasing the efficiency of the automobile fleet in use. Of
course, a combination of these two broad approaches can be used as well. However,
increasing gasoline taxes has been highly controversial, so most policy discussions
have focused on ways (in addition to CAFE) to increase the efficiency of motor
vehicles.
The Hydrogen Fuel Initiative and FreedomCAR
One potential strategy to improve vehicle fuel economy is to replace petroleum-
fueled internal combustion engines with fuel cell vehicles run on hydrogen fuel. Fuel
cell vehicles have the potential for much higher efficiency than combustion engines.
However, the technology is far from commercialization due to issues of cost, fuel
supply, and safety. Therefore, interest at the federal level has focused on research
and development of fuel cells, hydrogen storage systems, and methods for producing
and delivering hydrogen fuel.
In 2002, the Administration announced the FreedomCAR partnership, a new
initiative to focus federal and private research and development on fuel cell vehicles.
Further, in 2003 the Administration announced the President’s Hydrogen Fuel
Initiative, which increases funding for research on hydrogen fuel and fuel cells for
non-transportation applications. Over five years, the Administration is sought a total
funding increase of $720 million for these initiatives. These initiatives fund research
on hydrogen fuel and fuel cells for transportation and stationary applications.
Critics of the Administration initiatives have suggested that the hydrogen
program was intended to forestall attempts to significantly raise vehicle CAFE
standards, and that it relieves the automotive industry of assuming more initiative in
pursuing technological innovations. In addition, critics argue that hydrogen-fueled
vehicles may ultimately be infeasible, and that attention and funding should be
focused on other research areas. On the other hand, supporters argue that it is
appropriate for government to become involved in the development of technologies
that are too costly to draw private sector investment. At issue for these policymakers
will be whether the federal initiative and level of funding is aggressive enough.5
4 For more information, see U.S. Environmental Protection Agency (EPA), Regulatory Fact
Sheet: EPA Issues New Test Methods for Fuel Economy Window Stickers
, December 2006.
5 For additional information, see CRS Report RS21442, Hydrogen and Fuel Cell R&D:
FreedomCAR and the President’s Hydrogen Fuel Initiative
, by Brent D. Yacobucci.

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Recently, much attention has shifted away from research on hydrogen to research on
plug-in hybrids and advanced vehicle batteries.
Price of Gasoline
Owing to higher taxation of gasoline in other nations, Americans have enjoyed
some of the lowest prices for gasoline. The price of gasoline has increased
significantly and has approached in real terms the historic highs of the early 1980s.
Past proposals to raise the price of gasoline to leverage consumers into more efficient
vehicles have garnered little support. Owing to the relative price inelasticity of
gasoline demand, many believe that the size of the price increase required to curb
gasoline consumption to any degree would have a damaging effect on the economy
of several times greater magnitude. Indeed, analysis of the research (Plotkin, Greene,
1997, cited in References) suggested that an increase in gasoline taxes would be one-
third as effective in achieving a reduction in demand as studies of the 1980s once
projected. This is a significant reflection of the place that personal transportation and
inexpensive gasoline have assumed in our economy and value system.
Some have argued during past episodes of high prices that, when prices
softened again, the federal government should step in and capture the difference as
a tax, and possibly devote the proceeds to developing public transportation
infrastructure and incentives. This tax could be adjusted periodically to see that
gasoline would not become less expensive than a certain level in real (inflation
adjusted) dollars.
Owing to the unpopularity of raising gasoline prices, raising the CAFE standard
is more comfortable for some; however, it is a long-term response. Depending upon
the magnitude of an increase in gasoline prices, no matter what the cause, a price-
induced conservation response could be nearly immediate, and may grow as
consumers initially drive less and eventually seek out more efficient vehicles.
CAFE and Reduction of Carbon Dioxide Emissions
Vehicles account for one-fifth of U.S. production of CO emissions. There is
2
some debate over whether raising the CAFE standards would be an effective or
marginal way to reduce emissions of carbon dioxide. On one hand, improvements
in fuel economy should enable the same vehicle to burn less fuel to travel a given
distance. However, to the extent that technologies to improve fuel economy add cost
to new vehicles, it has been argued that consumers will tend to retain older, less
efficient cars longer. It has also been suggested that there is a correlation between
improved fuel economy and an increase in miles driven and vehicle emissions.
Vehicle miles traveled have continued to increase in recent years when fuel economy
improved only slightly.
Perhaps the most significant current issue regarding automotive fuel economy
is the decision by the state of California to require carbon dioxide emissions
standards for passenger cars and light trucks. Enacted in 2002, A.B. 1498 requires
the state to promulgate regulations to achieve the maximum feasible and cost-
effective reduction of greenhouse gases from cars and trucks. The regulations,

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adopted by the California Air Resources Board on September 24, 2004, require a
reduction of greenhouse gas emissions of 30% by 2016. The regulation covers
passenger vehicles, but would not affect heavier vehicles such as commercial trucks
or buses.
Under the Clean Air Act, California is permitted to establish its own pollutant
emissions standards for automobiles, as long as those standards are at least as
stringent as the federal standard. However, there is no current federal standard for
greenhouse gas emissions; federal standards focus on pollutants with direct effects
on air quality and health, including ground-level ozone (smog) and carbon monoxide.
Critics challenge the assertion that greenhouse gases are pollutants and contend that
the greenhouse gas standard is a de facto fuel economy standard, because reducing
emissions of carbon dioxide — the key greenhouse gas — requires reductions in fuel
consumption. Under CAFE, states do not have the authority to set their own
standards; authority remains solely with the federal government. California has
countered that carbon dioxide is a pollutant, and that there are considerable health
effects from global warming.
Several auto manufacturers and dealers have challenged the California auto
greenhouse gas standard in court. (Central Valley Chrysler-Jeep, Inc., vs.
Witherspoon, No. 1:04-CV-06663
, E.D. Cal., filed December 7, 2004.) The plaintiffs
argue that California lacks the authority to set a fuel economy standard under CAFE,
and that greenhouse gases are not a pollutant under the Clean Air Act. California
officials maintain that they have the authority under the Clean Air Act to regulate
vehicle greenhouse gas emissions.
The outcome of this case will likely have major effects on the U.S. auto
industry. If the standards are upheld, New York (and other states) will adopt
California’s standards, and other states are likely to follow suit. The state of
California estimates that complying with the standard could cost $1,000 per vehicle
by 2016, while opponents argue that costs could be as much as $3,000 per vehicle.
While reducing greenhouse gas emissions and fuel consumption, the new standards
would likely increase purchase costs and potentially diminish the new car market.
Further, it is likely that the standards would have varying effects on automakers who
sell more or less efficient products.
On April 2, 2007, the Supreme Court issued its ruling on a related case
(Commonwealth of Massachusetts v. EPA). In that case, 12 states and the District of
Columbia challenged the Environmental Protection Agency’s (EPA’s) decision not
to regulate greenhouse gas emissions from automobiles, arguing that EPA has the
responsibility to set greenhouse gas standards for passenger vehicles. Under that
decision, EPA is required to establish greenhouse gas standards for automobiles or
explicitly justify why such standards are not feasible. The decision in that case will
likely affect the outcome of the case against California. (For additional background,
see CRS Report RL32764, Climate Change Litigation: A Growing Phenomenon, by
Robert Meltz.)

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For Additional Reading
National Research Council. Committee on the Effectiveness and Impact of Corporate
Average Fuel Economy Standards. Effectiveness and Impact of Corporate
Average Fuel Economy (CAFE) Standards
. Washington, D.C., National
Academy Press, 2001. 166 p.
Greene, D.L., P.D. Patterson, M. Sing and J. Li. (2004). “Feebates, Rebates and
Gas-Guzzler Taxes: A Study of Incentives for Increased Fuel Economy,”
Energy Policy, vol. 33, no. 6, pp. 721-827, June 2004.
U.S. Congressional Budget Office. Reducing Gasoline Consumption: Three Policy
Options. November 2002. 36 p.
U.S. Congressional Budget Office. The Economic Costs of Fuel Economy Standards
Versus A Gasoline Tax. December 2003. 37 p.
U.S. Environmental Protection Agency. Fuel Economy Labeling of Motor Vehicles:
Revisions To Improve Calculation of Fuel Economy Estimates. 71 Federal
Register
77871. December 27, 2006.
U.S. Department of Transportation. National Highway Traffic Safety
Administration. Light Truck Average Fuel Economy Standards, Model Years
2005-2007. 68 FR 16867; April 7, 2003.
U.S. Department of Transportation. National Highway Traffic Safety
Administration. Automotive Fuel Economy Program. Annual Update,
Calendar Year 2004. [http://www.nhtsa.dot.gov/staticfiles/DOT/
NHTSA/Vehicle%20Safety/CAFE/2004_Fuel_Economy_Program.pdf]
U.S. Federal Register. Department of Transportation. National Highway Traffic
Safety Administration. Average Fuel Economy Standards for Light Trucks
Model Years 2008-2011
. Final Rule. Vol. 71, No. 66. Thursday, April 6, 2006,
pp. 17566-17679. [http://www.nhtsa.dot.gov/staticfiles/DOT/NHTSA/
Rulemaking/Rules/Associated%20Files/2006FinalRule.pdf]
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